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Abstract
[...]suspected kidney stone formers who had characteristic symptoms (pain or gross hematuria) that were clinically attributed to a stone, but confirmation was lacking (ie, imaging was deferred and the patient did not report actually seeing a voided stone). In women, the relative increase in incidence rate per 5 years was higher and then lower for ages 18 to 39 years to 40 to 59 years to 60 years or more (1.28 vs 1.33 vs 1.26; P=.003 for group-level interaction). Because women 60 years or older started at a lower incidence rate in 1984, the absolute increase in incidence rate by 2012 was higher for ages 18 to 39 years (190/100,000 personyears) and for ages 40 to 59 years (180/ 100,000 person-years) than for ages 60 years or more (107/100,000 person-years). Imaging technologies such as ultrasound and plain radiography were more widely used historically, but are known to be inferior for detecting kidney stones compared with CT scan.23,24 One hypothesis is that these stones missed without CT scan would previously have been suspected stones, but there was no proportional decline in suspected symptomatic stones with the increase in confirmed symptomatic stones. [...]past patients with small symptomatic kidney stones that resolved with spontaneous passage may have gone undiagnosed or had a nonspecific diagnosis such as back or flank pain. [...]it is difficult to separate out detection bias from true increases in kidney stone burden because there has been a progressive increase in the use of more accurate imaging modalities for diagnosing stones from 1984 to 2012.